Number of acyclic graphs on {1,2,...,n} such that the node with label 1 is in the same connected component (tree) as the node with label 2.
A220690
Number of acyclic graphs on {1,2,...,n} such that the node with label 1 is in the same connected component (tree) as the node with label 2.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =4a(4) =24a(5) =198a(6) =2110a(7) =27768a(8) =436656a(9) =8003950a(10) =167779068a(11) =3961727820a(12) =104102329504
External references
- oeis: A220690